5a8d | pdb_00005a8d

The high resolution structure of a novel alpha-L-arabinofuranosidase (CtGH43) from Clostridium thermocellum ATCC 27405

spinqualitylabelsall models 5a8d, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5a8d is a 1 chain structure with sequence from Acetivibrio thermocellus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, GOL, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A3DEX4_ACET2 Publication Abstract from PubMed The recent division of the large glycoside hydrolase family 43 (GH43) into subfamilies offers a renewed opportunity to develop structure-function studies aimed at clarifying the molecular determinants of substrate specificity in carbohydrate-degrading enzymes. alpha-L-Arabinofuranosidases (EC 3.2.1.55) remove arabinose side chains from heteropolysaccharides such as xylan and arabinan. However, there is some evidence suggesting that arabinofuranosidases are substrate-specific, being unable to display a debranching activity on different polysaccharides. Here, the structure of Clostridium thermocellum arabinofuranosidase 43A (CtAbf43A), which has been shown to act in the removal of arabinose side chains from arabinoxylan but not from pectic arabinan, is reported. CtAbf43A belongs to GH43 subfamily 16, the members of which have a restricted capacity to attack xylans. The crystal structure of CtAbf43A comprises a five-bladed beta-propeller fold typical of GH43 enzymes. CtAbf43A displays a highly compact architecture compatible with its high thermostability. Analysis of CtAbf43A along with the other member of GH43 subfamily 16 with known structure, the Bacillus subtilis arabinofuranosidase BsAXH-m2,3, suggests that the specificity of subfamily 16 for arabinoxylan is conferred by a long surface substrate-binding cleft that is complementary to the xylan backbone. The lack of a curved-shaped carbohydrate-interacting platform precludes GH43 subfamily 16 enzymes from interacting with the nonlinear arabinan scaffold and therefore from deconstructing this polysaccharide. Molecular determinants of substrate specificity revealed by the structure of Clostridium thermocellum arabinofuranosidase 43A from glycosyl hydrolase family 43 subfamily 16.,Goyal A, Ahmed S, Sharma K, Gupta V, Bule P, Alves VD, Fontes CM, Najmudin S Acta Crystallogr D Struct Biol. 2016 Dec 1;72(Pt 12):1281-1289. Epub 2016 Nov 29. PMID:27917828 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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